Previous tubular writer constructions, such as German Pat. No. 1,561,856 employ a cylindrical body which is screwed into the front of a casing element. The casing element is open in the rear and has a ring shaped stop upon which the ink supply chamber, especially and typically an ink cartridge, can be placed. The ink therefore enters the casing element from the rear and then flows through the inside bore of the cylindrical body to the writing tube.
Cleaning of the cylindrical body, and particularly of the ink compensating chamber, in such previously known tubular writers required that the cylindrical body be screwed out in a forward direction from the casing or sleeve element. According to experience this was a difficult procedure since drying ink gums up the threads used for fastening of the cylindrical body and the casing element together. As a result the screwing out of the cylindrical body could often be carried out only with great difficulty. Moreover, the relatively sensitive cylindrical bodies of these types of tubular writers would have to be unscrewed from the casing element for the purpose of cleaning and separately cleaned as an individual part. During such a cleaning operation one must also be careful that the tubular writer is held and maintained in an essentially perpendicular position, so that the ink held within both the ink supply chamber and the inside space of the casing element will not run out whenever the cylindrical body must be removed from the casing element for cleaning.
Another known tubular writer construction is exampled by German Pat. No. 2,010,355, which corresponds to U.S. Pat. No. 3,734,633, where the cylindrical body is developed in one piece so as to house the ink supply chamber, and the casing element covering up the ink compensating chamber is removable in a foward direction from the cylindrical body. Because this casing element can be removed in a forward direction, a relatively simple exposure and cleaning of the ink compensating chamber is possible, without any particular difficulties as a result of ink which is still present in the ink supply chamber. The ink supply chamber remains connected with the rear end of the cylindrical body during this cleaning process so that no ink can flow from it and merely the ink compensating chamber is exposed.
The remaining difficulty, or disadvantage, in the case of this second known tubular writer construction consists essentially in the fact that a complete disassembling of the tubular writer is required in order to clean the ink compensating chamber. As a result this requires handling and manipulation of two completely separate parts, namely the cylindrical body and the casing element.